Spinning turbine

ABSTRACT

A spinning turbine in which the turbine itself is rotatable within a closed stationary housing in which a pressure below atmospheric is to be maintained. The shaft of the turbine which is to be rotatably mounted outside of the housing, preferably on indirect bearing means, extends through a slightly larger bore in the back wall of the housing or in an annular flange on this back wall so as to form an intermediate annular slot. One or both walls of the slot and/or the back wall of the turbine and/or the inner side of the back wall of the housing are provided with annular grooves which form air chambers to prevent air from passing from the outside to the interior of the housing.

United States Patent 091 1111 3,797,962

Stahlecker Mar. 19, 1974 SPINNING TURBINE 963.593 7/1910 Legros 4l6/l69 A [75] Inventor: Fritz Stahlecker, Bad Ueberkingen', FOREIGN PATENTS OR APPLICATIONS Germany 15,487 0/1913 Great Britain 415/[69 A [731 essence l Stah'eck" 5533?? 1811338 81222 3222211111: ...::::::I 53212? Relchenbach Germany 1.093.628 11/1960 Germany 415/170 R [22] Filed: Jan. 25, 1972 A Primary Examiner-Henry F. Raduazo [2]] Appl' 220597 Attorney, Agent, or Firm-Craig and Antonelli [30] Foreign Application Priority Data [57] ABSTRACT Jan. 27, 1971 Germany 2103718 A p g turbine in the turbine itself is r0tat able within a closed stationary housing in which a [if] :LSil. 4lS/IFIS3IdZZ7/SZ pressure below atmospheric is to be maintained. The 27 shaft of the turbine which is to be rotatably mounted I d 0 care 2 1 outside of the housing, preferably on indirect bearing l meana, 9 9 9.95 h u h htl ,l299 51 h 56 R f C d back wall of the housing or in an annular flange on 1 e erences this back wall so as to form an intermediate annular UNITED STATES PATENTS slot. One or both walls of the slot and/or the back wall 3.367.099 2/l968 Kubovy et al 277/53 of the turbine and/or the inner side of the back wall of 2.729.106 l/l956 Mathiesen 74/5.7 the housing are provided with annular grooves which 835-336 lV1906 Schulz 3.77/57 form air chambers to prevent air from passing from 2.732.232 1/1956 whitiield 277/53 the outside to the interior of the housing 3,273,906 9/1966 Pennington 277/53 2.005.429 6/1935 Lichtenstein 277/53 13 Claims, 8 Drawing Figures PATENT 5mm 1 9 i974 SHEET 2 [IF 3 PATENTEDHAR 19 IB 3.797962 SHEET 3 BF 3.

W/ im E 1 f g &

SPINNING TURBINE The present invention relates to a spinning turbine which runs within a housing in which a pressure below atmospheric is maintained and the back wall of which is provided with a bore through which the shaft of the turbine passes which is rotatably mounted independently and outside of the housing, for example, on indirect bearing means.

It is already known to mount a spinning turbine within a closed housing in which, usually by the rotation of the turbine, a pressure below atmospheric is produced. which is required for the spinning operation. For reducing this pressure to a sufficiently low value, it is often additionally necessary to connect the turbine housing to a suction line. In any event, for maintaining this low pressure at a uniform value, it is necessary to prevent as much as possible the entry of air from the outside into the housing.

If the turbine shaft is mounted in a conventional manner directly in ball bearings in the housing, there is less danger that outside air may pass into the housing through the annular slot between the turbine shaft and the wall of the bore of the housing through which the shaft extends, since the grease in these bearings act as a packing. However. because of the suction toward the inside of the housing, there is a considerable danger that the grease of the turbine bearing will be drawn into the turbine chamber and soil the same and the material therein. Furthermore. when the turbine has run for a certain length of time, its bearings will no longer be sufficiently lubricated and will be worn prematurely.

For this reason it has been proposed more recently not to mount the turbine shaft directly but indirectly, for example, by supporting and driving it within the wedge-shaped gap between two pairs of supporting rollers. Such a bearing structure eliminates the danger that due to the reduced pressure within the housing the lubricant will be sucked out of the bearings and pass into the housing.

Such a turbine construction has. however, the disadvantage that air may easily pass from the outside through the bore for the turbine shaft in the back wall of the housing into the spinning chamber, especially since because of manufacturing tolerances the bore in this back wall must be considerably larger than the diameter of the turbine shaft or of a hub or collar on this shaft which passes through this bore. An annular slot is thus formed between the wall of the bore and the shaft through which air may pass from the outside into the interior of the housing. If the turbine shaft runs on supporting rollers. it is practically unavoidable that in the course of time the surfaces of these rollers will be worn with the result that their diameter will be reduced and the position of the turbine shaft relative to the axis of the bore in the back wall of the turbine housing will at least be slightly changed. This is one of the reasons why it is impossible to make the annular slot sufficiently small to prevent the entry of air from the outside into the housing. Therefore, if prior to this invention the shaft of a spinning turbine was mounted individually, it was impossible to prevent the entry of outside air into the housing and thus also an increase in pressure therein which might prevent a yarn attachment and is also very undesirable for the spinning operation.

It is an object of the present invention to provide a spinning turbine of the type as mentioned at the beginning in which the entry of outside air into the turbine housing will be substantially prevented without requiring the manufacturing tolerances of the turbine parts to be lowered below a value at which a quantity produc- 5 tion of these parts may still be carried out.

A principal feature of the present invention for attaining this object consists in designing the bore for the turbine shaft so as to form air stagnation or damming chambers and/or to provide such chambers within the area of the housing subsequent to the bore between the back wall of the housing and the adjacent rotating part or parts of the turbine. By providing such damming chambers. it is possible to attain an increased sealing effect without requiring any reduction of the size of the annular slot between the wall of the bore in the back wall of the turbine housing and the turbine shaft.

According to a simple embodiment of the invention, these damming chambers are provided in the form of annular grooves, preferably of a V-shaped cross section, in the rear wall of the spinning turbine which faces and is closely adjacent to the inner side of the back wall of the housing and/or in a hub or collar projecting from the back wall of the turbine. The sealing effect may be further improved by also providing similar annular grooves in the back wall of the housing and/or in the wall of the bore through which the turbine shaft or its hub or collar extends from the inside of the housing. In this manner it is possible to attain a cumulative sealing effect by providing a larger number of such air damming chamber behind each other, as seen in the direction from the outer end of the bore toward the inside of the housing.

Another feature of the invention consists in providing the back wall of the housing or a hublike projection thereon with one or more inserts, preferably of plastic which are provided with the bore through which the turbine shaft extends and in combination with the shaft and/or the back wall of the turbine also define the air damming chambers. These inserts have the advantage that in the manufacture of the turbine housing its tolerances do not have to be very small and that the insert or inserts themselves may be easily and accurately produced. According to one simple embodiment of the invention, the bore which is provided in the insert or inserts corresponds to the rotary part extending through this bore. that is. to the turbine shaft or the hub or collar on this shaft or on the back wall of the turbine, and the insert or inserts are preferably made of a material which has good antifriction properties. If this embodiment of the invention is employed, the diameter of the bore may be made relatively small as compared with the diameter of the rotary part extending through this bore since because of the antifriction properties of the stationary insert or inserts a slight engagement between the rotary part and the wall of the bore in the insert or inserts would be permissible during the running-in period of the turbine.

Another feature of the invention consists in adjustably securing the insert to the back wall of the turbine housing so as to permit the bore in the insert to be adjusted so as to extend coaxially to the turbine shaft. This feature also permits the bore to be made of a diameter only slightly larger than that of the rotary part extending through this bore, that is, of the shaft or the hub or collar on the back wall of the turbine, since the bore may be accurately centered relative to the shaft during the assembly of the turbine or even subsequently if a wear of the bearing means of the shaft which are separate and spaced from the housing causes a slight displacement of the shaft. According to another embodiment of the invention, such a centering of the bore relative to the turbine shaft or to the hub or collar on the back wall of the turbine may also be effected by making the insert of a cylinderical outer shape, by inserting it into a large bore in the back wall of the housing so as to permit it to be turned therein, and by providing the bore in the insert eccentrically to its outer surface. The insert may then be adjusted so that its bore extends coaxially to the turbine shaft by turning it within the back wall of the housing.

As already indicated above, the sealing effect even of a narrow annular slot between the wall of the bore in the insert and the turbine shaft or the hub or collar on the back wall of the turbine may be further increased by providing the wall of the bore in the insert with annular grooves which serve as air damming chambers. These annular grooves may also be of different diameters so as to form a step-shaped series of grooves, and the hub or collar which connects the back wall of the turbine with the shaft and may be integral either with the back wall or the shaft or both of them may be provided with a step-shaped series of cylinderical surfaces of different diameters slightly smaller than those of the surfaces of the annular grooves with which they are operatively associated to define air damming chambers. The air damming chambers may, however, also be formed, for example, by providing annular projections and intermediate recesses of different diameters on the back wall of the turbine and by providing the insert with similar projections which engage into the annular recesses of the back wall of the turbine. Instead of providing the annular projections on the back wall of the turbine, they may also be provided on a separate rotary element which may be either secured to the turbine itself within the housing or be mounted on its shaft outside of the housing.

Another feature of the invention consists in providing the back wall of the turbine and/or a part of its hub or collar with vanes or the like which during the rotation of the turbine tend to produce an air current from the inside toward the outside of the housing which increases the sealing effect of the annular slot between the turbine shaft or the hub or collar and the wall of the bore in the housing or in the insert and at least prevents the entry of outside air through this slot into the housing or may even produce a suction upon the inside of the housing and the spinning chamber so as to lower the pressure therein to a still greater extent.

These and additional features and advantages of the present invention will become further apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIG. 1 shows, partly in cross section, a first embodiment of the invention;

FIG. 2 shows a similar view of a second embodiment of the invention;

FIG. 3 shows a similar view of an embodiment of the invention which forms a combination of the embodiments as shown in FIGS. 1 and 2;

FIG. 4 shows a similar view of a modification of the embodiment as shown in FIG. 2;

FIG. 5 shows a similar view of another embodiment of the invention;

FIG. 6 shows a similar view of a further embodiment of the invention;

FIG. 7 shows a similar view of a further embodiment of the invention; while FIG. 8 shows a similar view of a modification of the embodiment as shown in FIG. 7.

In the drawings, FIG. 1 illustrates a spinning turbine -l which is freely rotatable within a housing 2 in which a pressure below atmospheric prevails during the spinning operation. At the front side of the spinning turbine l, the housing 2 is adapted to be tightly closed by a cover, not shown, which may be removed or pivoted to its open position. Although the low pressure in housing 2 may be produced by the rotation of the turbine 1 within this closed housing, such a pressure is often not sufficiently low. The wall of housing 2 may then be provided with one or more connections 3 to which a suction line may be connected.

The shaft 4 of the spinning turbine 1 extends through the back wall 5 of housing 2 and is indirectly mounted at the outside of this housing in a manner not shown in an air suspension bearing or on two pairs of rollers or the like. The back wall 5 of housing 2 is provided with a tubular hub or flange 6 which has a bore 7 through which the turbine shaft 4 extends. For the reasons as already stated and especially because of the manufacturing tolerances which should be allowed in a quantity production of such spinning turbines, the bore 7 should be made of such a size that an annular slot remains between the turbine shaft 4 and the wall of the bore 7. In order to prevent the entry of air into the inside of housing 2, several air stagnation or damming chambers 8 are provided behind each other subsequent to the annular slot. The lower wall of the turbine l which is located closely adjacent to the inner side of the back wall 5 of housing 2 is for this purpose provided with a plurality of annular grooves 9 of a V-shaped cross section. These air damming chambers 8 will interfere to such an extent with an air current which might possibly occur that the entry of air from the outside into the housing will be substantially prevented.

FIG. 2 illustrates an embodiment of the invention which is functionally similar to the embodiment according to FIG. 1, but in which the air damming chambers 10 are formed within the bore 7 in the flange or hub 6 on the back wall 5 of housing 2. The wall of bore 7 is for this purpose provided with a plurality of annular V-shaped grooves 11 which are associated with corresponding annular grooves 12 which are provided in the peripheral surface of the hub 13 of the spinning turbine l which extends through the bore 7. The opposite V- shaped grooves 11 and 12 in the walls of the bore 7 and the hub 13 then together form air damming chambers of a substantially rectangular cross section.

FIG. 3 illustrates another embodiment of the invention in which the rear side of the spinning turbine 1 is provided with annular V-shaped grooves 9 like those shown in FIG. 1. These grooves 9 are laterally offset by the maximum width of a half groove relative to similar annular V-shaped grooves 14 in the inner side of the bottom wall 5 of the housing so that the V-shaped projections on one wall project into the V-shaped grooves in the other wall. A labyrinth gland is thus formed which extends from the inner end of bore 7 toward the inside of the housing 2. The wall of bore 7 is further provided with annular grooves 11 like those shown in FIG. 2 so that additional air damming chambers 10 are formed. The hub of this spinning turbine l is, however, cylindrical and not provided with annular grooves.

FIG. 4 illustrates another embodiment of the invention which is functionally similar to the embodiment as shown in FIG. 2. The wall of bore 7 through which the turbine shaft 4 or a shaft part 16 of a larger diameter extends is also in this case provided with annular grooves 11 which form several air damming chambers behind each other. In this embodiment, however, the bore 7 with the annular grooves 11 in its wall isprovided in a cylindrical insert 17 which is mounted in the back wall 5 of housing 2 and in the tubular flange 6 thereon. Bore 7 extends eccentrically to the outer peripheral surface of the insert 17. Before the spinning turbine is inserted into the housing 2, the insert 17 is turned so that the axis of bore 7 coincides exactly with the axis of rotation of the shaft and the enlarged part 16 thereof so that a very small annular slot may be attained.

For preventing the entry of outside air to a still greater extent into the housing, the wall of bore 7 may be provided with a continuous thread flute instead of annular grooves 11, so that an outwardly directed air current through this flute is formed during the rotation of the turbine. This may apply likewise to the embodiments as shown in FIGS. 1 to 3.

In the further embodiment of the invention as illustrated in FIG. 5, the back wall 5 of housing 2 is likewise provided with a large aperture into which an insert 18 is fitted which preferably consists of plastic and is provided with a bore 19 through which the turbine shaft 4 is passed. This bore 19 in the insert 18 is step-shaped, and from the inside toward the outside of the housing each step has a smaller diameter than the previous step. Underneath its bottom, turbine 1 is provided with a step-shaped hub or collar 20 the individual steps of which are likewise of diminishing diameters. A stepshaped gland is thus formed which is provided with a succession of air damming chambers in the direction of bore 19. The ring of this collar 20 which is immediately adjacent to the bottom of the spinning turbine l and has the largest diameter is provided with vanes 21 or the like which during the rotation of the turbine form air conveying means which produce an air current through the step-shaped annular slot between bore 19 and collar 20 in the direction from the inside to the outside of the housing. In this embodiment of the invention. the effect of the air damming chambers is increased by the additional air conveying means which may be designed so that either a stagnation of air will occur in the annular slot between the walls of bore 19 and the collar 20 or that additional air will be sucked out of the housing 2 and the degree of the vacuum in the housing will be further increased.

FIG. 6 shows an embodiment of the invention in which the back wall 5 of the housing 2 and the flange thereon are provided with two separate inserts 22 and 23. These two inserts are cup-shaped and are spaced from each other by a chamber 24 around the enlarged collar 25 of turbine 1. These inserts 22 and 23 are made of a material with good antifriction properties and are provided with coaxial bores 26 which have a diameter nearly equal to the diameter of collar 25 so that only a very small annular slot will be formed between the collar 25 and the walls of the bores 26 in the two inserts 22 and 23 and any friction which might occur between these surfaces during the running-in period of the turbine will be negligable because of the good antifriction properties of the material of the inserts 22 and 23. After the running-in period of the turbine, collar 25 will be disengaged entirely from the walls of the bores 26 so that no further friction will occur.

In the further embodiment of the invention as illustrated in FIG. 7, an insert 27 which preferably consists likewise of plastic is fitted into an aperture in the back walls 5 of the housing and has a bore 29 the diameter of which differs only very slightly from the diameter of the collar 28 on the turbine 1.

A lower surface of the insert 27 engages upon the upper surface of the back wall 5 of the housing to which it is adjustably secured by screws. Due to this adjustability, the annular slot between the wall of bore 29 and the collar 28 may be made very small even though the manufacturing tolerances of the different parts as required for a quantity production may be of sufficient sizes. Before the turbine 1 is inserted into the housing and the turbine shaft 4 is passed through the bore 29, the insert 27 is accurately centered relative to the axis of rotation of the turbine by a special gauge which is preferably supported on the turbine bearings, not shown. This adjustment eliminates the effects of the manufacturing tolerances which otherwise might seriously interfere with the operation of the turbine. Thus, there will be no danger that the collar 28 may engage with the wall of bore 29 even if the annular slot between them is made very small. Although such a narrow annular slot will already prevent the entry of outside air into the housing 2 considerably, this effect may be increased by providing the insert 27 with annular recesses 30 into which corresponding projections on a rotary element 31 engage which is mounted on the turbine shaft 4. A step-shaped gland is thus formed between the stationary insert 27 and the rotary element 31 which additionally stops the entry of outside air into the housing 2.

The further embodiment of the invention as illustrated in FIG. 8 functionally corresponds substantially to the embodiment as shown in FIG. 7. Upon the outer side of the back wall 5 of housing 2 an insert 32 is centered and secured by screws. This centering operation is carried out by means of a special gauge which is supported on the bearing or parts of the bearing means of the turbine shaft 4 which are not shown. Bore 33 therefore only needs to be slightly larger than the diameter of the turbine shaft 4. The resulting annular slot'between the wall of bore 33 and the turbine shaft 4 is therefore so narrow that the entry of outside air into the housing 2 will be substantially prevented. Similarly as shown in FIG. 7, the insert 32 is provided on its inner side with an annular recess 34 into which a cylindrical projection 35 engages which is provided on the rear side of the spinning turbine l. A step-shaped gland is thus formed which additionally interferes with the entry of outside air in the housing 2.

If desired, it is possible in all embodiments of the invention to design the rotary parts themselves as air conveying means or to mount such means thereon which tend to produce a suction in the annular slot and in the housing in the direction toward the outside of the housing.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. A spinning turbine comprising: a rotary turbine element having a back wall and a collar portion, a shaft having said collar portion force-fitted on one end thereof, a stationary housing enclosing said turbine element, means for maintaining said stationary housing at a pressure below atmospheric pressure during the operation of said turbine, said housing including a back wall spaced slightly from said back wall of said turbine element forming a first narrow annular slot, said housing back wall being provided with a bore, said bore being provided in an extension of said housing back wall which substantially corresponds to the length of said collar portion, said shaft and said collar portion being disposed in said bore with said shaft extending to the outside of said housing, said bore having a diameter slightly larger than the diameter of said shaft and said collar portion extending there-through thereby forming a second narrow annular slot between the wall of said bore and the wall of said collar portion, said second narrow annular slot being in communication with said first annular slot, at least one of said walls being provided with a plurality of continuous recesses forming air damming chambers for substantially preventing air to pass from the outside of said stationary housing through said annular slot to the inside of said housing.

2. A spinning turbine as defined in claim 1, wherein said recesses form annular grooves in at least one of said walls.

3. A spinning turbine as defined in claim 1, wherein said recesses form associated annular grooves of a substantially similar cross-sectional shape in opposite parts of at least two of said walls, said associated grooves together forming larger air damming chambers.

4. A spinning turbine as defined in claim 1, further comprising at least one insert mounted in an aperture in the back wall of said housing and containing said bore.

5. A spinning turbine as defined in claim 4, in which said insert consists of plastic.

6. A spinning turbine as defined in claim 4, in which said insert consists of a material having good antifriction properties, and in which during the first period of operation of said turbine after its production said bore in said insert has a diameter nearly equal to the diameter of the part of said shaft extending through said bore.

7. A spinning turbine as defined in claim 4, in which said insert is adjustable relative to the bottom wall of said housing to permit said bore to be centered relative to the part of said shaft extending through said bore, and means for securing said insert in the adjusted position to said back wall of said housing.

8. A spinning turbine as defined in claim 7, in which said aperture in the back wall of said housing and the outer peripheral surface of said insert are substantially cylindrical and of substantially the same diameter, said insert being adapted to be turned to different positions within said aperture, said bore in said inset extending eccentrically to said outer surface thereof.

9. A spinning turbine as defined in claim 4, in which parts of the back wall of said turbine element and of said insert face each other and each of said parts has annular projections and annular recesses between said projections, said projections of one of said parts engaging into said recesses of the other part but the walls of said interengaging projections and recesses being slightly spaced from each other so as to form annular gaps, said gaps forming said air damming chambers.

10. A spinning turbine as defined in claim 4, further comprising a rotary member secured to and rotatable with said shaft outside of said housing and said insert, parts of said rotary member and of said insert directly facing each other and each having annular projections and annular recesses between said projections, said projections of one of said parts engaging into said recesses of the other part but the walls of said interengaging projections and recesses being slightly spaced from each other so as to form annular gaps, said gaps forming said air damming chambers.

' 11. A spinning turbine as defined in claim 1, in which the wall of said bore and the peripheral surface of said shaft part extending through said bore form associated annular steps, said steps decreasing in diameter from the inner side of the back wall of said housing and from the back wall of said turbine element toward the outer side of said housing wall, said steps of said shaft part having slightly smaller diameters than the associated steps of the wall of said bore so as to form said annular slot between said associated steps, said slot having a step-shaped cross section and forming said air damming chambers.

12. A spinning turbine as defined in claim 1, further comprising air conveying means connected to and rotatable with said turbine element for drawing air from the inside of said housing to the outside.

13. A spinning turbine as defined in claim 12, in which said air conveying means consist of vanes on said shaft part within said bore.

4i t I; m 

1. A spinning turbine comprising: a rotary turbine element having a back wall and a collar portion, a shaft having said collar portion force-fitted on one end thereof, a stationary housing enclosing said turbine element, means for maintaining said stationary housing at a pressure below atmospheric pressure during the operation of said turbine, said housing including a back wall spaced slightly from said back wall of said turbine element forming a first narrow annular slot, said housing back wall being provided with a bore, said bore being provided in an extension of said housing back wall which substantially corresponds to the length of said collar portion, said shaft and said collar portion being disposed in said bore with said shaft extending to the outside of said housing, said bore having a diameter slightly larger than the diameter of said shaft and said collar portion extending there-through thereby forming a second narrow annular slot between the wall of said bore and the wall of said collar portion, said second narrow annular slot being in communication with said first annular slot, at least one of said walls being provided with a plurality of continuous recesses forming air damming chambers for substantially preventing air to pass from the outside of said stationary housing through said annular slot to the inside of said housing.
 2. A spinning turbIne as defined in claim 1, wherein said recesses form annular grooves in at least one of said walls.
 3. A spinning turbine as defined in claim 1, wherein said recesses form associated annular grooves of a substantially similar cross-sectional shape in opposite parts of at least two of said walls, said associated grooves together forming larger air damming chambers.
 4. A spinning turbine as defined in claim 1, further comprising at least one insert mounted in an aperture in the back wall of said housing and containing said bore.
 5. A spinning turbine as defined in claim 4, in which said insert consists of plastic.
 6. A spinning turbine as defined in claim 4, in which said insert consists of a material having good antifriction properties, and in which during the first period of operation of said turbine after its production said bore in said insert has a diameter nearly equal to the diameter of the part of said shaft extending through said bore.
 7. A spinning turbine as defined in claim 4, in which said insert is adjustable relative to the bottom wall of said housing to permit said bore to be centered relative to the part of said shaft extending through said bore, and means for securing said insert in the adjusted position to said back wall of said housing.
 8. A spinning turbine as defined in claim 7, in which said aperture in the back wall of said housing and the outer peripheral surface of said insert are substantially cylindrical and of substantially the same diameter, said insert being adapted to be turned to different positions within said aperture, said bore in said inset extending eccentrically to said outer surface thereof.
 9. A spinning turbine as defined in claim 4, in which parts of the back wall of said turbine element and of said insert face each other and each of said parts has annular projections and annular recesses between said projections, said projections of one of said parts engaging into said recesses of the other part but the walls of said interengaging projections and recesses being slightly spaced from each other so as to form annular gaps, said gaps forming said air damming chambers.
 10. A spinning turbine as defined in claim 4, further comprising a rotary member secured to and rotatable with said shaft outside of said housing and said insert, parts of said rotary member and of said insert directly facing each other and each having annular projections and annular recesses between said projections, said projections of one of said parts engaging into said recesses of the other part but the walls of said interengaging projections and recesses being slightly spaced from each other so as to form annular gaps, said gaps forming said air damming chambers.
 11. A spinning turbine as defined in claim 1, in which the wall of said bore and the peripheral surface of said shaft part extending through said bore form associated annular steps, said steps decreasing in diameter from the inner side of the back wall of said housing and from the back wall of said turbine element toward the outer side of said housing wall, said steps of said shaft part having slightly smaller diameters than the associated steps of the wall of said bore so as to form said annular slot between said associated steps, said slot having a step-shaped cross section and forming said air damming chambers.
 12. A spinning turbine as defined in claim 1, further comprising air conveying means connected to and rotatable with said turbine element for drawing air from the inside of said housing to the outside.
 13. A spinning turbine as defined in claim 12, in which said air conveying means consist of vanes on said shaft part within said bore. 